Exposure and Response Prevention (ERP), which is a type of Cognitive behavioural therapy (CBT), is the most effective treatment for OCD.
In ERP, there are 2 parts:
"Exposure": expose yourself to the feared thoughts, images, objects and urges which begin your obsessions
"Response Prevention": make a choice not to engage in a compulsive behaviour when the anxiety or obsessions have been provoked
When you do not perform the compulsive behaviour in response to the obsession, eventually there will be a natural decrease in your anxiety level. This process is called "habituation".
The chief medicines prescribed are a kind of antidepressant named selective serotonin reuptake inhibitors (SSRIs).
By raising the level of serotonin, a chemical in your brain, an SSRI can help alleviate OCD symptoms.
It may take 12 weeks for taking an SSRI to see any benefits
International OCD Foundation. (n.d.). Exposure and Response Prevention (ERP).
National Health Service. (2019, November 18). Treatment - Obsessive Compulsive Disorder.